Combined resistor and fuse



Dec. 25 1928. I 1,696,605

H. P. HOLLNAGEL COMBINED RESISTOR AND FUSE Filed Jan. 1926 2Sheets-Sheet 1 To Line Fig. 3.

/2 Inventor:

' Herbert l H0 lnugel,

His'Attorneg.

TB App orat us H. P. HOLLNAGEL COMBINED RESISTOR AND FUSE Filed Jan. 6,1926 2 Sheets-Sheet 2 Fig. 4. FL 5.

ZII

F T0 LINE. '2 6 Inventor Herbert p. HoLLnageL T0 APPARATUS- PatentedDec. 25, 1928.

UNITED STATES PATENT orrlca.

HERBERT P. HOLLNAGEL, OF SWAMPSOOTT, MASSACHUSETTS, ASSIGNOR TO GENERALELECTRIC COMPANY, A CORPORATION OF NEW YORK.

COMBINED RESISTOR AND FUSE.

Application filed January The present invention relates to protectivedevices for electrical apparatus and especially for protecting againstthe destructive action of high potential, high frequency currents orsurges of electricity having a steep characterized by transient or surgephenomena originating anywhere in the circuit 16 to thereby protect suchapparatus or po'rtions of the circuit conductor as are liable to injuryfrom such phenomena.

One of the instances Where serious troubles have been experienced, fromelectrical transients is in condenser installations which, as iswellknown, areusually made up of a plurality of units, of substantialcapacity, ]o1ned in parallel, In practice condensers probably.

fail because of-tran'sients originating from causes remote to thecondenser., In the failure of a condenser, it is probable thattransients are set up by the sudden breakdown of some one unit and theensuing openin of the circuit thereto by the functioning of a se 0 I a I1n. These transients probably cause 1ncipient failure in the othercondenser unit's joined in arallel therewith, ultimately-resultinginteir breakdown,

5 It is well known that the resistance of conductors increasesienormously with rise in diameter of the conductors, their permeabil ityand resistivit I makeuse of the constant current 0 aracteristic, of theconductors, and these characteristics in their relationto trans ents, byconnecting in series tected thereby quietly and without causing ,F

orother protective device intercalated there-- with a fuse, anon-inductive resistance con-- 6, 1928, Serial No. 79,683.

sorb the energy produced by the sudden rise 1n voltage or a possibleensuing risein frequency, or both. 1

Certain embodiments of the invention are shown in the accompanyingdrawing, in

which Fig. 1 is a side elevation of a cartridge .fuse with anon-inductive resistor element combined therewith; Fig. 2 is a verticalsection thereof; Fig. 3 is a circuit diagram;

ig. 4 is an elevation of a modification in which the cartridge fuse ismounted alongside a non-inductive resistor element provided --withdissipating'vanes; Fig. 5 is an elevation of a further modification inwhich non-inductive resistor elements with dissipating vanes are mountedupon both ends of the cartridge fuse, and Fig. 6 is a circuit diagram ofthe latter arrangement.

The resistor member, as shown, consists of a base 1 of insulation havinga coil of insulated resistance wire 2 reversely or noninductively woundabout the larger end of the base and protected by an incasement of tapeor other fibrous material wrapped thereabout. The coil lead wires 4 and5 are threaded through passageways 6 and 7 in the smallend of the base.1

' The fuse member is similar to the ordinary cartridge fuse andcomprises a tubular barrel 8 of insulation with a thimble-shaped.terminal 9 at .its lower end and a ferrule-shaped terminal 10 at itsupper end. Theupper end of the barrel receives the smaller end of thebase which is secured therein by set screws 11.

The fusible element 12 is the ordinary metal strip surrounded by atubular envelope -13 .of sheet asbestos. The lower end of the fusibleelement 12 is attached to the terminal 9 and the upper end to a metalbush 1-1 secured to the lower end of the base.

The coil lead wire 4 is secured to the terminal 10 and the other leadwire 5 is attached to the bush 14, and the complete device is.

connected in circuit by insertion in the usual fuse block with thecontact: terminal 10 next the power line andthe terminal 9 next thecondenser unit to be protected, as indicated in Fig. 3. 1

U on the interruption of the current to the con enser unit by blowing ofthe fuse under short circuit, a surge of current takes place whichdissipates its energy in the non-inductive resistance coil 2 withoutcausing disturbance of other devices connected to the circuit.

To care for the situation where continued arcing or interrupted shortcircuit COIlFlltlQIlS persist in the line, as a consequence of whichcontinued or interrupted transients of a relatively high frequencypersist over a period of time, and resulting in the absorption of energyby the resistor, I provide the latter with dissipative means.

As shown in Fig. 4, the energy dissipative means consists of a helicalvane or Archimedean spiral 1-5 of metal coiled about a core bar 16having metal thimbles 17 at its ends adapted to enter contact clips 18,the lower of which is provided with a binding screw 19 for connectionwith the line wire. 'The in sulated resistance wire 2 is connectedat oneend by a binding screw 20 to the lower thimble 17 and passed through thetrough of the spiral 15 to the upper end thereof where it turns about apeg 21 carried by bar 16 and rep-asses through the spiral trough to thelower end thereof and joined by a binding screw 22 to the lower contactclip 23 of the enclosed fuse 8. The resistor clips 18 and the fuse clips23 are mounted on an insulating base so as to support the resistor andthe fuse beside each other and permit renewal of the latter withoutdisturbance of the former. Vith the resistance wire 52 protected byinsulation, the core bar 16 may be of either insulating or conductingmaterial, but in case the latter material is used it is provided with aslot parallel to its axis in order that it may function as anopen-c-ircuited secondary in the presence of the variable currentscarried by the resistance wire. In some cases it also is advantageous toprovide the radiating vanes with cross slots at intervals for a likepurpose. v

As shown in Fig. 5, the end terminals of the cartridge fuse 8', areprovided with-hollow insulating core bars 16", on each of which ismounted a spaced series of metal disks or washers 2-1 and the insulatedresistance wire 2" is connected by a binding screw 25 to the respectivefuse terminals and passed through "the innermost washer 24 and coiledrightlow bar 16''. to connect with the fusible-element as in'the firstmodification.

Fig. 6 shows a diagram of connections embodied in the fuse constructionof Fig. 5 and from which it will be apparent, that the noninduetiveresistance disposed at both ends of the fusible link serves to limit thetransient efie'ct thereon in both directions. Transients arising fromthe continuance of an are as a result of fusion of the fuse link aredissipated not only before the entering line but also before enteringtheapparatus, thus. protecting against surge or transient phenomenaduring both alternations of each cycle of such frequenciesl \Vhile Ihaveshown and described the best embodiments of the invention known tome, I do not desire to be restricted thereto.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is,

1. The combination of an electric fuse, spaced metallic vanes,'and areversely wound resistance coil connected in series with said fuse andhaving its convolutions distributed in the spaces between said vanes. v

2. The combination of a fuse member comprising afusible element enclosedin an insulating cartridge having external contacts, and a non-inductiveresistance member comprising an insulating base mounted on saidcartridge and supporting a coil of resistance conductor woundnon-inductively and connected in series to said fusible element and saidfusible element and said resistance con ductor having terminalconnection with said external contacts, and radiating vanes so disposedas to radiate the energy developed by said resistance conductor.

3. The combination of a fusible element,

an insulating cartridge about said element,

a non-inductive resistance member mounted on said cartridge andconnected in series with said element, and means also mounted on saidcartridge to radiate energy from said resistance member.

4. The combination of a fusible element, an insulating cartridge aboutsaid element, a non-inductive resistance member mounted on saidcartridge and connected inseries with said element, and metallic vanesalso mounted on said cartridge to radiate energy from said resistancemember.

In witness whereof, I have hereunto set my hand this fourth day ofJanuary, 1926.

HERBERT P. HOLLNAGEL.

